Hand held and other miniature computers are increasingly coming into use. Examples are the ROLODEX REX from Franklin Electronic and the PALM PILOT from 3Com, both of which are hand held personal digital assistants whose functionality includes a digital calendar, a "to do" list, and a phone list. "Computer" herein is used in its broadest sense to refer to any device capable of performing logic functions.
A drawback of hand held computers generally is the difficulty of expanding their functionality by the addition of hardware elements. For example, the ROLODEX REX can only download data by connecting into a PCMCIA type II slot, and hardware elements cannot be added to it to expand its functionality. Similarly, the PALM PILOT can only perform software and information downloads and uploads by connecting with a docking station.
Accordingly, there is a need for a technique by which the functionality of a hand held computer can be expanded quickly and easily by interconnecting the hand held computer to a variety of accessory devices, without destroying the hand held characteristic of the combination.